Application of Dimethyl Carbonate Assisted Chemical Looping Technology in the Separation of the Ethylene Glycol and 1,2-Butanediol Mixture and Coproduction of 1,2-Butene Carbonate

1,2-Butene carbonate (BC) is an important five-membered cyclic carbonate with a high commercial value, but its massive production is limited by the lack of raw material 1,2-butanediol (1,2-BDO). 1,2-BDO is coproduced with ethylene glycol (EG) in the hydrogenation process in the coal-to-EG route, one-pot conversion of biomass to liquid fuels and chemicals, and fermentation of broths. However, the separation and purification of 1,2-BDO are difficult. In this paper, an intensified reactive distillation process for the separation of the EG and 1,2-BDO azeotropic mixture via dimethyl carbonate assisted chemical looping technology and coproduction of BC and EG products is proposed. The transesterification reactions of EG and 1,2-BDO were investigated individually in the presence of basic resin catalyst KIP321, and the kinetic parameters were imbedded into Aspen plus (V11) for the design of the reactive distillation column to perform the transesterification process. The proposed flowsheet, which includes the transesterification unit, a DMC and methanol separation unit, and an EG recovery unit, was designed and simulated. Remarkably, the conversions of diols are over 0.998, the yield of 1,2-butylene carbonate is 99.86%, and the yield of the EG product is theoretically 100%, which shows excellent potential for industrial application.